Window treatment, namely the art of decorating the interior of a window, has been subject to fashion change over the years. Earlier in the century spring-loaded pull up shades and two-inch blinds called venetian blinds were in vogue. In the sixties, the use of drapes rather than blinds or shades was commonly practiced by interior decorators of that time. In the early seventies, Roman shades, which were rolled up from the bottom toward the top by a drawstring, were considered chic. In the late seventies mini-blinds, i.e. those of one-inch depth came into fashion as the preferred window treatment.
Today, the mini-blind continues to be fashionable along with the pleated shade. Pleated shades are constructed of horizontal pleats of a single piece of fabric. They operate much like the shades of old in that viewing can only take place when the shades are drawn open, i.e. raised upwardly from the bottom of the window. Blinds on the other hand offer viewing capability without the necessity of raising them. The blind permits the slats to be oriented parallel to one another, thereby letting light in from the window.
Both children and infirm individuals can operate mini-blinds to change the condition from light emitting to light prevention with minimal effort, in contrast to the operation of a shade or pleated shade.
Examples of blind systems and shades are found in a number of U.S. Patents. U.S. Pat. No. 2,231,778 to Swanson discloses a typical traditional venetian blind. This blind uses tape ladders to hold and align the slats. The system has a mechanism for turning a headpiece that raises and lowers the tapes, thereby opening and closing the slats. Traditionally, the slats were wide and the system was heavy.
U.S. Pat. No. 2,512,594 to Burnes discloses a vertical form of blinds. Burnes states that this design prevents the buildup of dust on the blinds and makes them easier to operate than the horizontal blinds. One change in this design is that the vertical slats overlap when closed. When open, they look like ordinary vertical blinds. When closed, the overlapping slats block all light from entering the room, making them more efficient than the standard horizontal blinds. The overlap is achieved by making the slats wider than the space between adjacent slats. Thus, when closed, the end of one vertical slat overlaps the adjacent slat.
U.S. Pat. No. 2,247,260 to Stone discloses a typical pleated shade. Here, a solid shade is positioned between a head rail and a bottom rail. The bottom rail can be lifted to open the shade. Unlike blinds, however, there are no slats to open when the shade is closed.
Although shades and blinds have worked well over the years, there have been attempts to improve their design. Most blinds leak light, either through the gaps between the slats, or through slots in the slats that the rope ladders pass through. One innovative design is found in U.S. Pat. No. 4,076,068 to Archer et al. In this design, the blinds are positioned between two panes of glass. Thus, the blinds are an integral part of the window itself. When the slats are closed, there are two lines of slats, spaced apart. This acts to reduce the amount of light passing through the blinds to a minimum. Unfortunately, because the blinds are installed within the window, maintenance is difficult. Moreover, changing the color or style of blinds is no easy task.
U.S. Pat. No. 3,851,699 to Shapiro teaches a system of vertical drapes that have xe2x80x9cblind-likexe2x80x9d characteristics. The drapes are an alternate set of panels. Light transmitting panels are interposed adjacent to light impeding panels. When the drapes are open, the light transmitting panels are aligned parallel to a light source, while the light impeding panels are orthogonal to the light transmitting panels. When closed, the light impeding panels fold over the light transmitting panels, thereby blocking out the light.
U.S. Pat. No. 2,757,727 issuing to Findell, discloses a system of curved slats. Each curved slat has two curved pieces that rest on a carrier. When open, the slats look like ordinary slats. When closed, the slats are open on one end. The tops of the lower slats contact the bottoms of the slats immediately above them. This produces a continuous overlapped row of slats that works to prevent light leakage between the slats. Although this system may be more effective at limiting light transmission, the system uses thick slats that limit light transmission when open, and are bulkier than a flat set of blinds when closed.
U.S. Pat. No. 4,628,979 issuing to Pei-Shun Hsu discloses a window blind having a plurality of horizontal slats that can be regulated to simulate a pleated window.
U.S. Pat. No. 4,651,794 to Bytheway Jr. attempts to solve the problem of light leakage by designing a set of blinds that when closed, take on the form of a pleated shade. This system uses a number of curved slats that are connected to two ladder systems. In this way, the slats alternate when the blind is closed, forming a series of xe2x80x9cVxe2x80x9d shaped panels. These panels take on the appearance of a pleated shade. This works because the rear end of one slat is rotated down to meet the rear end of the slat immediately below it, while the front end of the lower slat is lowered to meet the front end of the next lower slat that rises to meet it. The pattern is repeated for the entire length of the blind. The difficulty with this design is the complex system needed to move the slats in an alternate configuration such as (up, down, up, down, etc.) This not only increases costs, but also increases the likelihood of operating problems with the blinds over time.
U.S. Pat. No. 4,708,188 issuing to Bytheway Jr. discloses two pair of cable ladders, which move in opposite directions, to move alternate slats in opposite directions.
U.S. Pat. No. 5,558,146 issuing to Makio Abe discloses a blind having transparent base boards and graphic patterns to selectively block or reflect light.
The overlapping blind apparatus comprises first and second ladder strings which are biased by a first pulley rod in either clockwise or counter-clockwise directions. When the second ladder string is pulled up, the first ladder string is pulled down. Bridging strings are provided in spaced, parallel relation between the first and second ladder strings. A first slat and a second slat are joined at one end to form a hinged slat. Multiple sets of hinged slats are sized to cover a window opening. The slats may be vertically or horizontally aligned. First louver strings are attached to the center of each of the first slat portions, and to the second ladder string. When the first pulley is rotated counter-clockwise, the first slat portions are biased open while the second slat portions are biased away from the first slat portions, to form a V-slat configuration. When the blinds are fully extended, the first slat rests against the bottom of the next adjacent second slat, providing an overlap, which effectively blocks light leakage through the slats. When the first pulley rod is rotated clockwise, the first and second slats tilt, yet remain in a substantially closed, parallel alignment similar to existing mini-blinds. A central lifting string is provided to raise or lower the horizontal overlapping blinds. The central string does not hamper the operation of the horizontal overlapping blinds, because the first slats have an elongated aperture similar to the elongated aperture in the second slat, to allow the central draw string to pass therethrough. Indicia may be placed on the first and second slats. This invention may be adapted for either horizontal or vertical alignment of the blinds.
Objects and advantages of this invention will become apparent by reference to the following description and accompanying drawings.